1. Field of the Invention
The present invention relates to a package structure, in particular, to an embedded electronic device package structure.
2. Description of Related Art
The complication of semiconductor devices has been increased, and at least part of the reasons is due to user's demands for increasing processing speed and decreasing the sizes of the devices. Although the advantages of increasing processing speed and decreasing sizes of the devices are significant, it also causes property issue of the semiconductor device. In particular, higher clock speed may increase the frequency of converting signal level, such that the electromagnetic emission with higher frequency or shorter wavelength is increased. Electromagnetic emission can be radiated out from a source semiconductor device and emitted into a neighboring semiconductor device. If the electromagnetic emission emitting toward the neighboring semiconductor device is strong enough, the electromagnetic emission may affect operation of the (neighboring) semiconductor device. This phenomenon sometimes is called electromagnetic interference (EMI). Semiconductor devices with smaller size suffer from EMI issue more seriously, because the semiconductor devices (with smaller sizes) are disposed in an electronic system with higher density, such that the neighboring semiconductor devices receive stronger and unwanted electromagnetic emission.
One way to diminish the electromagnetic interference is to shield one set of semiconductor devices in the semiconductor device package. In particular, by disposing grounding conductive casing or conductive housing at the outside of the package structure, shielding effect is achieved. When the electromagnetic emission radiating from the inside of the package structure toward the inner surface of the casing, at least part of the electromagnetic emission is shorted, so as to diminish the strength of the electromagnetic emission which is capable of penetrating the casing and effects the operation of the neighboring semiconductor devices. Similarly, when the electromagnetic emission radiates from the neighboring semiconductor device toward the outer surface of the casing, the similar shorted situation happens, so as to diminish the electromagnetic interference affecting the semiconductor devices in the package structure.
However, even though the conductive casing may diminish the electromagnetic interference, there are a lot of disadvantages in using the conductive casing, for example, the casing generally is fixed at the outside of the semiconductor device package by adhesive paste, and because the stickiness of the adhesive paste may decrease due to temperature, humidity and other environmental factors, the casing may easily peel off or fall off. Moreover, the size and the shape of the casing need to correspond to the size and the shape of the package structure, thus, different sizes and shapes of semiconductor device packages need to go with different casings to contain different package structures. This would further increase production cost and time. More importantly, the casing covering the outside of the semiconductor device would increase the volume of the package structure, so the package volume can not be effectively decreased, and this type of casing can not be applied to embedded electronic device package structure with higher package density, which is against the market demands for light, thin, short, small, high density, and function-integrated electronic products.